In Patent Literature 1, a micro-machined interferometer is disclosed. This interferometer includes optical components such as a beam splitter, an electrostatic actuator, a movable mirror movable by the electrostatic actuator, and a fixed mirror. In addition, a method of manufacturing such an interferometer is disclosed in Patent Literature 1. In this manufacturing method, a portion serving as each optical component is formed on an insulating layer by etching a silicon layer of an SOI wafer. In addition, in this manufacturing method, metal coating is selectively performed on a portion formed of a movable mirror or a fixed mirror through sputtering using a shadow mask.